Expanded uses of surfactant therapy

Outcomes at 7 Years of Age of Former Very Preterm Neonates with Repeated Surfactant Treatment for Prolonged Respiratory Distress in the Neonatal Period

This study aimed at evaluating the 7-year outcomes of 118 very preterm newborns (VPNs, gestational age = 26 ± 1.4 w) involved in a randomized controlled trial. They presented neonatal respiratory distress (RDS), requiring ventilation for 14 ± 2 days post-natal age (PNA). A repeated instillation of 200 mg/kg poractant alfa (SURF) did not improve early bronchopulmonary dysplasia, but the SURF infants needed less re-hospitalization than the controls for respiratory problems at 1- and 2-year PNA. There was no growth difference at 7.1 ± 0.3 years between 41 SURF infants and 36 controls (80% of the eligible children), and 7.9% SURF infants vs. 28.6% controls presented asthma (p = 0.021). The children underwent cognitive assessment (WISC IV) and pulmonary function testing (PFT), measuring their spirometry, lung volume, and airway resistance. The spirometry measures showed differences (p < 0.05) between the SURF infants and the controls (mean ± standard deviation (median z-score)) for FEV1 (L/s) (1.188 ± 0.690(-0.803) vs. 1.080 ± 0.243 (-1.446)); FEV1 after betamimetics (1.244 ± 0.183(-0.525) vs. 1.091 ± 0.20(-1.342)); FVC (L) (1.402 ± 0.217 (-0.406) vs. 1.265 ± 0.267 (-1.141)), and FVC after betamimetics (1.452 ± 0.237 (-0.241) vs. 1.279 ± 0.264 (-1.020)). PFT showed no differences in the volumes or airway resistance. The global IQ median (interquartile range) was 89 (82:99) vs. 89 (76:98), with 61% of the children >85 in both groups. Repeated surfactant treatment in VPNs presenting severe RDS led to the attenuation of early lung injuries, with an impact on long-term pulmonary sequelae, without differences in neurodevelopmental outcomes.

Ultra-slim flexible bronchoscopy-guided topical hemostatic drugs administration for the management of life-threatening refractory pulmonary hemorrhage in a preterm infant: Case report

Pulmonary hemorrhage (PH) is a rare acute catastrophic event with high mortality among neonates, especially preterm infants. Primary treatments included pulmonary surfactant, high-frequency oscillatory ventilation, epinephrine, coagulopathy management, and intermittent positive pressure ventilation. However, there are still challenges in diagnosing and treating refractory or focal pulmonary hemorrhages. Ultra-slim bronchoscopy has been widely used in the field of critically ill children and is increasingly being done in neonates with critical respiratory disease in recent years. In this study, we report a case with refractory pulmonary hemorrhage in premature infants, which was finally diagnosed as localized hemorrhage in the upper left lobe and cured by ultra-slim bronchoscopy-guided topical hemostatic drug administration. Bronchoscopy is an optional, safe, and practicable technique for early diagnosis and direct injection therapy of neonatal PH in managing life-threatening PH.

Surfactant nebulization therapy during NIPPV ventilation in surfactant-deficient newborn piglets

BACKGROUND

In recent years, nasal intermittent positive pressure ventilation (NIPPV) has been growing in popularity as a form of noninvasive ventilation for respiratory support in the initial treatment of neonates with surfactant (SF) deficiency. The combination of this type of ventilation with noninvasive SF administration (by nebulization) is an attractive treatment option for respiratory distress syndrome (RDS)-associated pathophysiology of the neonatal lungs. In this study, we aimed to test the tolerability and efficacy of SF nebulization during NIPPV for the treatment of neonatal RDS.

METHODS

Spontaneously-breathing newborn piglets (n = 6/group) with bronchoalveolar lavage (BAL)-induced RDS were assigned to receive during NIPPV (180 min): poractant alfa (400 mg/kg) via an investigational customized vibrating-membrane nebulizer (eFlow-Neos) or poractant alfa (200 mg/kg) as a bolus using the Insure method or no surfactant (controls).

MEASUREMENT AND RESULTS

We assessed pulmonary, hemodynamic and cerebral effects and performed histological analysis of lung and brain tissue. After repeated BAL, newborn piglets developed severe RDS (F_iO2 : 1, pH < 7.2, P_aCO2  > 70 mmHg, P_aO2 < 70 mmHg, C_dyn  < 0.5 ml/cmH₂ O/kg). In both SF-treated groups, we observed rapid improvement in pulmonary status and also similar hemodynamic, cerebral behavior, and lung and brain injury scores.

CONCLUSION

Our results in newborn piglets with severe BAL-induced RDS show the administration of nebulized poractant alfa using the eFlow-Neos nebulizer during NIPPV to be well tolerated and efficacious, suggesting that this noninvasive SF administration option should be explored further.

Surfactant for pulmonary haemorrhage in neonates

BACKGROUND

In the 1960s and 1970s, pulmonary haemorrhage (PH) occurred mainly in full-term infants with pre-existing illness with an incidence of 1.3 per 1000 live births. Risk factors for PH included severity of illness, intrauterine growth restriction, patent ductus arteriosus (PDA), coagulopathy and the need for assisted ventilation. Presently, PH occurs in 3% to 5% of preterm ventilated infants with severe respiratory distress syndrome (RDS) who often have a PDA and have received surfactant. The cause of PH is thought to be due to rapid lowering of intrapulmonary pressure, which facilitates left to right shunting across a PDA and an increase in pulmonary blood flow. Retrospective case reports and one prospective uncontrolled study have shown promising results for surfactant in treating PH.

OBJECTIVES

To evaluate the effect of surfactant treatment compared to placebo or no intervention on mortality and morbidities in neonates with PH.

SEARCH METHODS

For this update The Cochrane Library, Issue 2, 2012; MEDLINE; EMBASE; CINAHL; Clinicaltrials.gov; Controlled-trials.com; proceedings (2000 to 2011) of the Annual Meetings of the Pediatric Academic Societies (Abstracts2View) and Web of Science were searched on 8 February 2012.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that evaluated the effect of surfactant in the treatment of PH in intubated term or preterm (< 37 weeks) neonates with PH. Infants were included up to 44 weeks' postmenstrual age. The interventions studied were intratracheal instillation of surfactant (natural or synthetic, regardless of dose) versus placebo or no intervention.

DATA COLLECTION AND ANALYSIS

If studies were identified by the literature search, the planned analyses included risk ratio, risk difference, number needed to treat to benefit or to harm for dichotomous outcomes, and mean difference for continuous outcomes, with their 95% confidence intervals. A fixed-effect model would be used for meta-analyses. The risk of bias for included trials would be assessed. Heterogeneity tests, including the I2 statistic, would be performed to assess the appropriateness of pooling the data and the results would be reported.

MAIN RESULTS

No trials were identified.

AUTHORS' CONCLUSIONS

No randomised or quasi-randomised trials that evaluated the effect of surfactant in PH were identified. Therefore, no conclusions from such trials can be drawn. In view of the promising results from studies with less strict study designs than a randomised controlled trial, there is reason to conduct further trials of surfactant for the treatment of PH in neonates.

Short-term outcome of pulmonary hemorrhage in very-low-birth-weight preterm infants

BACKGROUND

Severe pulmonary hemorrhage is a serious complication with a high mortality rate in preterm infants with respiratory distress syndrome (RDS) after surfactant therapy. The aim of this study is to evaluate the efficacy of our current management strategy for neonates with severe pulmonary hemorrhage.

MATERIALS AND METHODS

Very-low-birth-weight (VLBW) infants who developed severe pulmonary hemorrhage were studied from January 2006 to August 2011. Treatment for severe pulmonary hemorrhage in our neonatal intensive care unit (NICU) included intratracheal epinephrine spraying/irrigation, blood component therapy, and as necessary, surfactant supplement therapy was administered in cases that secondary RDS was diagnosed. High frequency oscillatory ventilation (HFOV) was utilized when hypoxia or respiratory acidosis persisted under conventional mechanical ventilation (CMV). We then described the clinical courses of severe pulmonary hemorrhage following our management.

RESULTS

A total of 18 (3.2%) out of 469 VLBW infants developed severe pulmonary hemorrhage. The mean gestational age was 27 weeks, the mean birth weight was 822 g, and the onset age was 2.5 days after birth. There was no severe pulmonary hemorrhage-associated mortality during this period with the exception of one case, in which an infant died after the parents refused to do further therapy. Sixteen (88.8%) neonates had RDS and 13 received surfactant therapy. Twelve (66.6%) cases developed secondary RDS following the onset of severe pulmonary hemorrhage, and four cases received surfactant supplement therapy. In the surfactant supplement group, alveolar-arterial oxygen difference (AaDO2) and oxygenation index (OI) during the 2-4 hours postpulmonary hemorrhage period showed statistically significant improvement, whereas the other group only showed a tendency toward improvement without reaching statistical significance when compared to the baseline data. Duration of high oxygen requirement [defined as fraction of inspired oxygen (FiO2) > 40%] was also less in the surfactant supplement group.

CONCLUSION

This data suggests that our current strategy is effective for treating severe pulmonary hemorrhage in VLBW infants. Surfactant therapy for severe pulmonary hemorrhage may also be beneficial for improving lung function and may shorten the duration of high oxygen requirement.

Changes in hemodynamics after rescue surfactant administration

OBJECTIVE

To evaluate the hemodynamic changes occurring after rescue surfactant dosing in relation to the clinical respiratory response in preterm infants with respiratory distress syndrome.

STUDY DESIGN

We studied 20 infants who received surfactant (poractant alfa) after failing continuous positive airway pressure (CPAP) beyond 2 h of life. Consecutive echocardiograms were performed before the surfactant dose, 10 min after and 1 h after the surfactant dose. Superior vena cava flow, right ventricular output, atrial and patent ductus arteriosus diameter and direction of shunting were measured. A surfactant responder (SR) was defined as an infant whose inspired fraction of oxygen was reduced to air (0.21) by 3 h after surfactant administration. A surfactant non-responder (SNR) was defined as an infant who remained on more than 0.21 at 3 h postsurfactant administration. Concurrent physiological parameters (heart rate, transcutaneous CO2, mean arterial blood pressure, mean airway pressure) were also recorded. Subject characteristics were compared relative to noted hemodynamic effects.

RESULTS

Of the 20 infants enrolled in the study, 12 were SR. These infants received surfactant earlier and had increased measures of systemic blood flow after receipt of surfactant compared with baseline. SNR did not have changes in systemic blood flow from baseline after surfactant dosing. There was no change in ductal shunting or atrial shunting between the two groups.

CONCLUSIONS

A good clinical response to rescue surfactant is seen in infants who received surfactant earlier and is associated with increase in systemic blood flow. Timing of rescue surfactant administration needs to be further evaluated in larger prospective studies.

Surfactant for pulmonary haemorrhage in neonates

BACKGROUND

In the 1960s and 1970s, pulmonary haemorrhage (PH) occurred mainly in full-term infants with pre-existing illness with an incidence of 1.3 per 1000 live births. Risk factors for PH included severity of illness, intrauterine growth restriction, patent ductus arteriosus (PDA), coagulopathy and the need for assisted ventilation. Presently, PH occurs in 3% to 5% of preterm ventilated infants with severe respiratory distress syndrome (RDS) who often have a PDA and have received surfactant. The cause of PH is thought to be due to rapid lowering of intrapulmonary pressure, which facilitates left to right shunting across a PDA and an increase in pulmonary blood flow. Retrospective case reports and one prospective uncontrolled study have shown promising results for surfactant in treating PH.

OBJECTIVES

To evaluate the effect of surfactant treatment compared to placebo or no intervention on mortality and morbidities in neonates with PH.

SEARCH METHODS

For this update The Cochrane Library, Issue 2, 2012; MEDLINE; EMBASE; CINAHL; Clinicaltrials.gov; Controlled-trials.com; proceedings (2000 to 2011) of the Annual Meetings of the Pediatric Academic Societies (Abstracts2View) and Web of Science were searched on 8 February 2012.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that evaluated the effect of surfactant in the treatment of PH in intubated term or preterm (< 37 weeks) neonates with PH. Infants were included up to 44 weeks' postmenstrual age. The interventions studied were intratracheal instillation of surfactant (natural or synthetic, regardless of dose) versus placebo or no intervention.

DATA COLLECTION AND ANALYSIS

If studies were identified by the literature search, the planned analyses included risk ratio, risk difference, number needed to treat to benefit or to harm for dichotomous outcomes, and mean difference for continuous outcomes, with their 95% confidence intervals. A fixed-effect model would be used for meta-analyses. The risk of bias for included trials would be assessed. Heterogeneity tests, including the I(2) statistic, would be performed to assess the appropriateness of pooling the data and the results would be reported.

MAIN RESULTS

No trials were identified.

AUTHORS' CONCLUSIONS

No randomised or quasi-randomised trials that evaluated the effect of surfactant in PH were identified. Therefore, no conclusions from such trials can be drawn. In view of the promising results from studies with less strict study designs than a randomised controlled trial, there is reason to conduct further trials of surfactant for the treatment of PH in neonates.

Polyethylene glycol addition does not improve exogenous surfactant function in an experimental model of meconium aspiration syndrome

Meconium (MEC) is a potent inactivator of pulmonary surfactant. The authors studied the effects of polyethylene glycol addition to the exogenous surfactant over the lung mechanics and volumes. Human meconium was administrated to newborn rabbits. Animals were ventilated for 20 minutes and dynamic compliance, ventilatory pressure, and tidal volume were recorded. Animals were randomized into 3 study groups: MEC group (without surfactant therapy); S100 group (100 mg/kg surfactant); and PEG group (100 mg/kg porcine surfactant plus 5% PEG). After ventilation, a pulmonary pressure-volume curve was built. Histological analysis was carried out to calculate the mean alveolar size (Lm) and the distortion index (DI). Both groups treated with surfactant showed higher values of dynamic pulmonary compliance and lower ventilatory pressure, compared with the MEC group (P < .05). S100 group had a larger maximum lung volume, V(30), compared with the MEC group (P < .05). Lm and DI values were smaller in the groups treated with surfactant than in the MEC group (P < .05). No differences were observed between the S100 and PEG groups. Animals treated with surfactant showed significant improvement in pulmonary function as compared to nontreated animals. PEG added to exogenous surfactant did not improve lung mechanics or volumes.

Surfactant for pulmonary hemorrhage in neonates

BACKGROUND

In the late 1960's and 1970's, pulmonary hemorrhage (PH) occurred mainly in full term infants with severe pre-existing illness. The incidence of PH was quoted as 1.3 per 1,000 live births. In the older medical literature, the risk factors associated with PH included the severity of the associated illness, intrauterine growth restriction, patent ductus arteriosus (PDA), coagulopathy, and the need for assisted ventilation. Presently, PH occurs mainly in preterm ventilated infants with severe respiratory distress syndrome (RDS) who often have a PDA and have received surfactant. Currently, PH complicates the hospital course of 3-5% of preterm infants with RDS. Although not clear, the cause of PH is thought to be due to a rapid lowering of intrapulmonary pressure, which facilitates left to right shunting across a patent ductus arteriosus and an increase in pulmonary blood flow. Retrospective case reports and one prospective uncontrolled study that used surfactant for PH in neonates have shown promising results in treating PH.

OBJECTIVES

To evaluate the effect of surfactant treatment compared to placebo or no intervention on mortality in neonates with pulmonary hemorrhage. In addition, the review will evaluate the effect of surfactant treatment on neonatal morbidities associated with PH compared to placebo or no intervention.

SEARCH STRATEGY

The following databases were searched in January 2008: The Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 4, 2007) and MEDLINE from 1966 and EMBASE from 1980 to the time of the full review using the OVID interface. The proceedings of the Annual Meetings of the Pediatric Academic Societies and the European Society of Pediatric Research published in Pediatric Research or electronically on their web sites were searched from 1994 to the time of the full review. Science citation index (Web of Science) was searched for authors quoting key references of observational studies.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that evaluated the effect of surfactant in the treatment of PH in intubated term or preterm (< 37 weeks) neonates with PH. Infants were included up to 44 weeks postmenstrual age. Infants were included regardless of prior treatment with surfactant. The interventions studied were intratracheal instillation of surfactant (natural or synthetic, regardless of dose) vs. placebo or no intervention.

DATA COLLECTION AND ANALYSIS

If studies were identified by the literature search, the planned analyses included calculation of the relative risk (RR), risk difference (RD), number needed to treat (NNT) or number needed to harm (NNH) for dichotomous outcomes, and weighed mean difference (WMD) for continuous outcomes, with their 95% confidence intervals (CI). A fixed effects model would be used for meta-analyses. Heterogeneity tests, including the I- squared (I(2)) statistic, would be performed to assess the appropriateness of pooling the data and the results would be reported.

MAIN RESULTS

No trials were identified.

AUTHORS' CONCLUSIONS

No randomized or quasi-randomized trials that evaluated the effect of surfactant in PH were identified. Therefore, no conclusions from such trials can be drawn. In view of the promising results from studies with less strict study designs than a randomized controlled trial, there is reason to conduct further trials of surfactant for the treatment of PH in neonates.

Morphological alterations of exogenous surfactant inhibited by meconium can be prevented by dextran

Background

Surfactant dysfunction due to inhibition is involved in the pathophysiology of meconium aspiration syndrome. Dextran addition has been shown to reverse exogenous surfactant inactivation by meconium, but the precise mechanisms and the morphological correlate of this effect are yet unknown. Morphological surfactant analysis by transmission electron microscopy (TEM) and stereology allows the differentiation of active (large aggregates = LA) and inactive (small aggregates = SA) subtypes.

Methods

To determine the in vitro effects of meconium and dextran addition on the morphology of a modified porcine natural surfactant (Curosurf), Curosurf samples were either incubated alone or together with meconium or with meconium and dextran, fixed and processed for TEM. Volume fractions of surfactant subtypes [lamellar body-like forms (LBL), multilamellar vesicles (MV), unilamellar vesicles (UV)] were determined stereologically.

Results

All preparations contained LBL and MV (corresponding to LA) as well as UV (corresponding to SA). The volume fraction of UV increased with addition of meconium and decreased with further addition of dextran. Correspondingly, the UV/(LBL+MV) ratio (resembling the SA/LA ratio) increased when meconium was added and decreased when dextran was added to the surfactant-meconium mixture.

Conclusion

Meconium causes alterations in the ultrastructural composition of Curosurf that can be visualized and analyzed by TEM and stereology. These alterations resemble an increase in the SA/LA ratio and are paralleled by an increase in minimum surface tension. Dextran prevents these effects and may therefore be a useful additive to exogenous surfactant preparations to preserve their structural and functional integrity, thereby improving their resistance to inactivation.

New methods advance treatment for respiratory distress syndrome

The past 20 years of hard labor in neonatal respiratory distress have resulted in several important advances arising from our understanding of lung chemistry and physiology. Our knowledge of surfactant chemistry has enabled us to identify infants at high risk for developing neonatal distress due to surfactant deficiency, reducing this risk with antenatal corticosteroid treatment, and improving the neonatal outcome by means of administration of effective surfactant replacement. Recognition of the roles of oxygen toxicity and barotrauma in promoting lung injury has premitted the development of more effective means of assisted ventilation less likely to injure the lungs of severely ill infants with pulmonary failure. Nitric oxide has proven to be an effective pulmonary vasodilator and permits the successful treatment of patients with pulmonary hypertension who might previously have required an invasive surgical treatment to achieve a desirable clinical outcome.